Power plant analysis

Assume that kinetic and potential energy changes are negligible, and the system is at steady state. Assume that the natural gas is pure methane gas, and the surroundings are at 298.15 K. 

For the Rankine cycle, the operation is isentropic, and S2 = S3. However, S2 S3y, and the discharged steam from the turbine is wet steam. The quality of the wet steam x3s is 

The steam in the final state is also wet steam with a quality of x3 

With this quality, the entropy of the final state is 

Comparison of the two efficiencies shows that both operations have relatively low efficiencies, although the actual cycle is considerably less efficient than the Rankine cycle. 

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Example 4.24 Power plant analysis A steam power plant (Figure 4.29) uses natural gas to produce 0.12 MW power. A furnace completely burns the natural gas to carbon dioxide and water vapor with 40% excess air. The flue gas leaves the furnace at 500 K. The combustion heat supplied to a boiler produces steam at 10,000 kPa and 798.15 K, which is sent to a turbine. The turbine efficiency is 0.7. The discharged steam from the turbine is at 30kPa, and is sent to a condenser. The condensed water is pumped to the boiler. The pump efficiency is 0.90. Determine ... 

Here the A represents the difference between exit and entrance properties. The ke term is significant in analyzing the internals of a turbine, but at the component level in power plant analysis, pe and ke are not normally significant resulting in a simplified... 

M. MAYOS, A. SCHUMM, C. SOORS, O. VAILHEN, E. FLEUET Application of the PACE system to the analysis of multitechnique NDT data on a power plant component -Review of Progress in QNDE, vol. 16B, eds. D. Thompson and D.E. Chimenti, Plenum, 1997, pp. 2175-2182. 

This RCCA inspection methods has now already proven it s reliability as an industrial solution on two Belgian power plants (Doel 3 and Tihange 1). Thanks to the graphical programming language, each site feedback is immediately injected. This way of working ensures a permanent improvement of the analysis system, and a reduction in manpower for the analysis. 

Sodium and chloride may be measured using ion-selective electrodes (see Electro analytical techniques). On-line monitors exist for these ions. Sihca and phosphate may be monitored colorimetricaHy. Iron is usually monitored by analysis of filters that have had a measured amount of water flow through them. Chloride, sulfate, phosphate, and other anions may be monitored by ion chromatography using chemical suppression. On-line ion chromatography is used at many nuclear power plants. 

Swain A. and H. Guttman 1983. Handbook of human reliability analysis with emphasis on nuclear power plant applications (NUREG/CR-1278), Nuclear Regulatory Commission, Washington, DC. 

Seismie analysis is carried out for all important engineering structures such as dams, bridges and nuclear power plants. For regions where these are to be located the likely expectations of an earthquake as well as the extent of its magnitude must be assessed on the basis of the seismic history and the earthquake records of the region (Figures 14.12 to Figure 14.16). Based on these and other factors such as soil stratification, site dependent response spectra are determined. These are the RRS for equipment mounted... 

In the area of performance, the steam turbine power plants have an efficiency of about 35%, as compared to combined cycle power plants, which have an efficiency of about 55%. Newer Gas Turbine technology will make combined cycle efficiencies range between 60-65%. As a rule of thumb a 1% increase in efficiency could mean that 3.3% more capital can be invested. However one must be careful that the increase in efficiency does not lead to a decrease in availability. From 1996-2000 we have seen a growth in efficiency of about 10% and a loss in availability of about 10%. This trend must be turned around since many analysis show that a 1% drop in the availability needs about 2-3% increase in efficiency to offset that loss. 

The analysis of the different cycles examined here, which range from the simplest cycle such as evaporative cooling to the more complex cycles such as the humidified and heated compressed air cycle, are rated to their effectiveness and to their cost is shown in Table 2-1. The cycles examined here have been used in actual operation of major power plants, thus there are no cycles evaluated that are only conceptual in nature. The results show addition from 3-21% in power and the increase in efficiency from 0.4-24%... 

Aerothermal analysis This pertains to a detailed thermodynamie analysis of the full power plant and individual eomponents. Models are ereated of individual eomponents, ineluding the gas turbine, steam turbine heat exehangers, and distillation towers. Both the algorithmie and statistieal approaehes are used. Data is presented in a variety of performanee maps, bar eharts, summary eharts, and baseline plots. 

If a life cycle analysis were conducted the new costs of a plant are about 7-10% of the life cycle costs. Maintenance costs are approximately 15-20% of the life cycle costs. Operating costs, which essentially consist of energy costs, make up the remainder, between 70-80% of the life cycle costs, of any major power plant. Thus, performance evaluation of the turbine is one of the most important parameter in the operation of a plant. 

Often in plant operations condensate at high pressures are let down to lower pressures. In such situations some low-pressure flash steam is produced, and the low-pressure condensate is either sent to a power plant or is cascaded to a lower pressure level. The following analysis solves the mass and heat balances that describe such a system, and can be used as an approximate calculation procedure. Refer to Figure 2 for a simplified view of the system and the basis for developing the mass and energy balances. We consider the condensate to be at pressure Pj and temperature tj, from whence it is let down to pressure 2. The saturation temperature at pressure Pj is tj. The vapor flow is defined as V Ibs/hr, and the condensate quality is defined as L Ibs/hr. The mass balance derived from Figure 2 is ... 

Swain, A. D., and H. E. Guttmann (1983). Handbook of Human Reliability Analysis With Emphasis on Nuclear Power Plant Applications. NUREG/ CR-1278. Washington, DC United States Nuclear Regulatory Commission. 

FMEA is particularly suited for root cause analysis and is quite useful for environmental qualification and aging analysis. It is extensively used in the aerospace and nuclear ]iowei indiistrii-s but seldom used in PSAs, Possibly one reason for this is that FMEA, like parts count. ,s not chrectlv suita lundant systems such as those that occur in nuclear power plants Table i 4... 

The use of component logic models to build system fault logic has been discussed by several authors for chemical and electrical systems (Powers and Thompkins, 1974 Fussell, 197.S and Powers and Lapp, 1976). In addition, generic sabotage fault trees have been used for some time in the analysis of security concerns for nuclear power plants (NUREG /CR-0809, NUREG/CR. 121,... 

Loss of offsite power at nuclear power plants is addressed in EPRI NP-2301, 1982 giving data on the frequency of offsite power loss and subsequent recoveiy at nuclear power plants. Data analysis includes point estimate frequency with confidence limits, assuming a constant rate of occurrence. Recovery time is analyzed with a lognormal distribution for the time to recover. 

Given the damage states, the analysis flows much as shown in Figure 6.3-1, depending on the process. For a nuclear power plant, thermal-hydraulic analyses determine the spatial temperature of the damaged core, and consequently the ability of the core to retain radioactive materials. Analysis of the physical processes reveals the amounts of hazardous materials that may be released. 

For historical and regulatory reasons, a PSA of a nuclear power plant begins with the system analysis to determine the ways that an upset condition could occur, its probability... 

This chapter shows that chemical process systems may fail and have serious consequences to the workers, public and the environment. Comparing with Chapter 6, chemical processes are similar to the processes in a nuclear power plant, hence, they may be analyzed similarly because both consist of tanks, pipes heat exchangers, and sources of heat. As an example of analysis, we analyze a storage tank rupture. 

Two studies resolved the Unresolved Safety Issue A-44, "Station Blackout." The first siudy, The Reliability of Emergency AC Power Systems in Nuclear Power Plants," when combined uh die lelevant loss-oToffsite-power frequency, provides estimates of station-blackout frequencies lor 18 nuclear power plants and 10 generic designs. The study also identified the design and operational features most important to the reliability of AC power systems. The second study, "Station Blackout Accident Analysis" (NUREG/CR-3226), focused on the relative importance to risk of laiion blackout events and the plant design and operational features that would reduce this risk. 

Flood Event Frequency Estimates were developed from flooding events in nuclear power plants with adjustments for plant-specific features and data. The data were from the IPE Surry flood analysis, industry sources, and licensing event reports (LERs). Some plant specific models were developed for the circulating water (CW) and service water (SW) lines... 

The Safety Goal Policy Statement was published to define acceptable radiological risk IVom nuclear power plant operation, and by implication provide a de minimus risk to be assured without cost considerations. Safety beyond the minimum requires cost-benefit analysis. Since being promulgated, bulletins and generic letters have been imposed to enhance safety, under the provisions of 10 CFR 50.109, the Backfit Rule. 

Several initiating events are unique 1) large LOCA (6), 2) flow blockage events (4a. 4b, and 4d). and 3) fuel defects (4e). The analysis of these required special tools not found in coinmcrcial power plant PRAs. 

Baranowsky, P.W., A.M, Kolaczkowski, and M.A. Fedele, A Probabilistic Safety Analysis of DC Power Supply Requirements for Nuclear Power Plants, April 1981. 

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